network security and privacyshmat/courses/cs378_spring07/intro.pdf · command and control, burglar...

Vitaly Shmatikov

CS 361S

Network Security and Privacy

http://www.cs.utexas.edu/~shmat/courses/cs361s/

Course Personnel

Instructor: Vitaly Shmatikov

• Office: GDC 6.812

• Office hours: Tuesday, 1-2pm

• Open door policy – don’t hesitate to stop by!

TA: Oliver Jensen

• Office: GDC 6.818A

• Office hours: Wednesday, 11am-12n

Watch the course website

• Assignments, reading materials, lecture notes

Prerequisites

Required: working knowledge of C and JavaScript

• The first project is about Web security

• The second involves writing buffer overflow attacks in C

– You must have detailed understanding of x86 architecture, stack layout, calling conventions, etc.

Recommended: Introduction to Computer Security; Cryptography; Computer Networks; Compilers and/or Operating Systems

• Not much overlap with this course, but will help gain deeper understanding of security mechanisms and where they fit in the big picture

Course Logistics

Lectures

• Tuesday, Thursday 11a-12:30p

Three homeworks (30% of the grade)

Two projects (10 + 15% of the grade)

• A fair bit of C coding and PHP/JavaScript hacking

• Can be done in teams of 2 students

• Security is a contact sport!

Midterm (20% of the grade)

Final (25% of the grade)

UTCS Code of Conduct will be strictly enforced

No make-up or substitute exams!

If you are not sure you will be able to take the exams in class on the assigned

dates, do not take this course!

Late Submission Policy

Each take-home assignment is due in class at 11am on the due date

• 5 take-home assignments (3 homeworks, 2 projects)

You have 3 late days to use any way you want

• You can submit one assignment 3 days late, 3 assignments 1 day late, etc.

• After you use up your days, you get 0 points for each late assignment

• Partial days are rounded up to the next full day

Course Materials

Textbook:

Kaufman, Perlman, Speciner. “Network Security”

• Lectures will not follow the textbook

• Lectures will focus on “big-picture” principles and ideas of network attack and defense

• Attend lectures! Lectures will cover some material that is not in the textbook – and you will be tested on it!

Occasional assigned readings

• Start reading “Smashing the Stack For Fun and Profit” by Aleph One (from Phrack hacker magazine)

• Understanding it will be essential for your project

Other Helpful Books

Ross Anderson’s “Security Engineering”

• Focuses on design principles for secure systems

• Wide range of entertaining examples: banking, nuclear command and control, burglar alarms

“The Shellcoder’s Handbook”

• Practical how-to manual for hacking attacks

• Not a required text, but you may find it useful for the buffer overflow project

Kevin Mitnick’s “The Art of Intrusion”

• Real-world hacking stories

• Good illustration for many concepts in this course

Main Themes of the Course

Vulnerabilities of networked software

• Worms and botnets, denial of service, attacks on Web applications, attacks on infrastructure

Defensive technologies

• Protection of information in transit: cryptography, application- and transport-layer security protocols

• Protection of networked software: memory integrity, firewalls, antivirus tools, intrusion detection

Study a few deployed protocols in detail: from design principles to implementation details

• Kerberos, SSL/TLS, IPsec (if time permits)

What This Course is Not About

Not a comprehensive course on computer security

Not a course on ethical, legal, or economic issues

• No file sharing, DMCA, piracy, free speech issues

• No surveillance

Only a cursory overview of cryptography

• Take CS 346 for deeper understanding

Only some issues in systems security

• Very little about OS security, secure hardware, physical security, security of embedded devices…

Motivation

https://

Excerpt From “General Terms of Use”

YOU ACKNOWLEDGE THAT NEITHER WELLS FARGO, ITS AFFILIATES NOR ANY OF THEIR RESPECTIVE EMPLOYEES, AGENTS, THIRD PARTY CONTENT PROVIDERS OR LICENSORS WARRANT THAT THE SERVICES OR THE SITE WILL BE UNINTERRUPTED OR ERROR FREE; NOR DO THEY MAKE ANY WARRANTY AS TO THE RESULTS THAT MAY BE OBTAINED FROM USE OF THE SERVICES OR THE SITE, OR AS TO THE TIMELINESS, SEQUENCE, ACCURACY, RELIABILITY, COMPLETENESS OR CONTENT OF ANY INFORMATION, SERVICE, OR MERCHANDISE PROVIDED THROUGH THE SERVICES AND THE SITE.

“Privacy, Security and Legal”

“As a Wells Fargo customer, your privacy and security always come first.”

• Privacy policies

• Privacy policy for individuals

• Online privacy policy

• Social Security Number protection policy

• International privacy policies

• Your online security

• How we protect you

• Online security guarantee

• Fraud information center

• How fraudsters operate

• How to protect yourself

• USA PATRIOT ACT information

What Do You Think?

What do you think should be included in

“privacy and security” for an e-commerce website?

?

Desirable Security Properties

Authenticity

Confidentiality

Integrity

Availability

Accountability and non-repudiation

Access control

Privacy of collected information

…

Syllabus (1): Security Mechanisms

Basics of cryptography

• Symmetric and public-key encryption, certificates, cryptographic hash functions, pseudo-random generators

Authentication and key establishment

• Case study: Kerberos

Web security

• Case study: SSL/TLS

IP security (if time permits)

• Case study: IPsec protocol suite

Syllabus (2): Attacks and Defenses

Web attacks

• Cross-site scripting and request forgery, SQL injection

Network attacks

• Worms, viruses, botnets

• Spam, phishing, denial of service

• Attacks on routing and DNS infrastructure

Buffer overflow / memory corruption attacks

Defense tools

• Firewalls, antivirus, intrusion detection systems

Wireless security

Peek at the Dark Side

The only reason we will be

learning about attack techniques

is to build better defenses

Don’t even think about using

this knowledge to attack anyone

A Security Engineer’s Mindset [Bruce Schneier]

Ken Thompson

ACM Turing Award, 1983

“Reflections on Trusting Trust”

What code can we trust?

Consider "login" or "su" in Unix

• Is Ubuntu binary reliable? RedHat?

• Does it send your password to someone?

• Does it have backdoor for a “special” remote user?

Can't trust the binary, so check source code or write your own, recompile

Does this solve problem?

http://www.acm.org/classics/sep95


Who wrote the compiler?

Compiler looks for source code that looks the login process, inserts backdoor into it

Ok, inspect the source code of the compiler… Looks good? Recompile the compiler!

Does this solve the problem?



The compiler is written in C …

compiler(S) {

if (match(S, "login-pattern")) {

compile (login-backdoor)

return

}

if (match(S, "compiler-pattern")) {

compile (compiler-backdoor)

return

}

.... /* compile as usual */

}


“The moral is obvious. You can't trust code that

you did not totally create yourself. (Especially

code from companies that employ people like me.)”

slide 23

“Reflections on Trusting Trust” http://www.acm.org/classics/sep95

Network Stack

people

application

session

transport

network

data link

physical

IP

TCP

email, Web, NFS

RPC

802.11

Sendmail, FTP, NFS bugs, chosen-protocol and version-rollback attacks

SYN flooding, RIP attacks, sequence number prediction

IP smurfing and other address spoofing attacks

RPC worms, portmapper exploits

WEP attacks

Only as secure as the single weakest layer… … or interconnection between the layers

RF RF fingerprinting, DoS

Phishing attacks, usability

Network Defenses

Cryptographic primitives

Protocols and policies

Implementations

Building blocks

Blueprints

Systems

RSA, DSS, SHA-1…

TLS, IPsec, access control…

Firewalls, intrusion

detection…

All defense mechanisms must work correctly and securely

End uses People Password managers,

company policies…

Correctness versus Security

System correctness: system satisfies specification

• For reasonable input, get reasonable output

System security: system properties preserved in face of attack

• For unreasonable input, output not completely disastrous

Main difference: active interference from adversary

Modular design may increase vulnerability …

• Abstraction is difficult to achieve in security: what if the adversary operates below your level of abstraction?

… but also increase security (small TCB)

What Drives the Attackers?

Put up a fake financial website, collect users’ logins and passwords, empty out their accounts

Insert a hidden program into unsuspecting users’ computers, use it to spread spam or for espionage

Subvert copy protection for music, video, games

Stage denial of service attacks on websites, extort money

Wreak havoc, achieve fame and glory in the blackhat community

Marketplace for Vulnerabilities

Option 1: bug bounty programs

• Google: up to $3133.7 in 2010, now up to $20K per bug

• Facebook: up to $20K per bug

• Microsoft: up to $150K per bug

• Pwn2Own competition: $10-15K

Option 2: vulnerability brokers

• ZDI, iDefense: $2-25K

Option 3: gray and black markets

• Up to $100-250K reported (hard to verify)

• A zero-day against iOS sold for $500K (allegedly)

It’s a Business

Several companies specialize in finding and selling exploits

• ReVuln, Vupen, Netragard, Exodus Intelligence

• The average flaw sells for $35-160K

• $100K+ annual subscription fees

Nation-state buyers

• “Israel, Britain, Russia, India and Brazil are some of the biggest spenders. North Korea is in the market, as are some Middle Eastern intelligence services. Countries in the Asian Pacific, including Malaysia and Singapore, are buying, too” -- NY Times (Jul 2013)

Marketplace for Stolen Data

Single credit card number: $4-15

Single card with magnetic track data: $12-30

“Fullz”: $25-40

• Full name, address, phone, email addresses (with passwords), date of birth, SSN, bank account and routing numbers, online banking credentials, credit cards with magnetic track data and PINs

Online credentials for a bank account with $70-150K balance: under $300

Prices dropped since 2011, indicating supply glut

[Dell SecureWorks, 2013]

Marketplace for Victims

Pay-per-install on compromised machines

• US: $100-150 / 1000 downloads, “global mix”: $12-15

• Can be used to send spam, stage denial of service attacks, perform click fraud, host scam websites

Botnets for rent

• DDoS: $10/hour or $150/week

• Spam: from $10/1,000,000 emails

Tools and services

• Basic Trojans ($3-10), Windows rootkits ($300), email, SMS, ICQ spamming tools ($30-50), botnet setup and support ($200/month, etc.)

[Trend Micro, “Russian Underground 101”, 2012]

Bad News

Security often not a primary consideration

• Performance and usability take precedence

Feature-rich systems may be poorly understood

Implementations are buggy

• Buffer overflows are the “vulnerability of the decade”

• Cross-site scripting and other Web attacks

Networks are more open and accessible than ever

• Increased exposure, easier to cover tracks

Many attacks are not even technical in nature

• Phishing, social engineering, etc.

Better News

There are a lot of defense mechanisms

• We’ll study some, but by no means all, in this course

It’s important to understand their limitations

• “If you think cryptography will solve your problem, then you don’t understand cryptography… and you don’t understand your problem”

• Many security holes are based on misunderstanding

Security awareness and user “buy-in” help

Other important factors: usability and economics

Reading Assignment

Review Kaufman, section 1.5

• Primer on networking

Start reading buffer overflow materials on the course website

• “Smashing the Stack for Fun and Profit”

• You will definitely need to understand it for the buffer overflow project

network security and privacyshmat/courses/cs378_spring07/intro.pdf · command and control, burglar...

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